sublimehighRule

Attachment: Filename containing Unicode braille pattern blank character

Recursively identifies attachments that attempt to conceal their true file extension by using Braille Pattern Blank characters

MITRE ATT&CK

T1566.001 T1204.002 T1486 T1036 T1027

defense-evasion

Detection Query

type.inbound
and any(attachments,
        regex.icontains(.file_name, '\x{2800}')
        or (
          .file_extension in~ $file_extensions_common_archives
          and any(file.explode(.), regex.icontains(.file_name, '\x{2800}'))
        )
)

Author

vector_sec

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

References

Raw Content

name: 'Attachment: Filename containing Unicode braille pattern blank character'
description: |
  Recursively identifies attachments that attempt to conceal their true file extension by using Braille Pattern Blank characters
references:
  - "https://www.bleepingcomputer.com/news/security/windows-vulnerability-abused-braille-spaces-in-zero-day-attacks/"
  - "https://research.checkpoint.com/2024/resurrecting-internet-explorer-threat-actors-using-zero-day-tricks-in-internet-shortcut-file-to-lure-victims-cve-2024-38112/"
type: "rule"
authors:
  - twitter: "vector_sec"
severity: "high"
source: |
  type.inbound
  and any(attachments,
          regex.icontains(.file_name, '\x{2800}')
          or (
            .file_extension in~ $file_extensions_common_archives
            and any(file.explode(.), regex.icontains(.file_name, '\x{2800}'))
          )
  )
attack_types:
  - "Malware/Ransomware"
tactics_and_techniques:
  - "Evasion"
detection_methods:
  - "Archive analysis"
  - "File analysis"
id: "c230ca86-f563-58b0-8667-5052cc9bf3c6"